JPS6229388A - Color solid-state image pickup device - Google Patents

Abstract

PURPOSE:To decrease color shift and excellent picture by providing the 1st synthesis means color signals obtained from each solid-state image pickup element at a prescribed ratio and the 2nd synthesis means adding a low frequency component of each color signal and a high frequency component of the signal obtained from the 1st synthesis means. CONSTITUTION:R.G.B color signals obtained from the image pickup elements 1-3 are subject to processings such as sample-and-hold, gain adjustment and provision of time difference corresponding to 1/2 picture element pitch between the G and the R, B signals by pre-processing circuits 4-6. A low pass filter 17 extracts the low frequency component of the R.G.B color signals, a high pass filter 18 extracts a high frequency component of a broad band signal Y, a delay circuit 19 corrects the time shift by the filters 17, 18, the delay circuit 19 corrects the timewise shift by the filters 17, 18, low frequency components RL.GL.BL of the color signals R.G.B and a high frequency component YH of the broad band signal Y are added by an adder 20 to obtain color signals R'.G'.B'. Thus, the high frequency component of each color signal is replaced into the high frequency component YH of the broad band signal not including foled part and the folded component at the high frequency component of each color signal is eliminated to reduce moire of G-Mg and color shift.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a color solid-state imaging device that obtains high-resolution color images using three solid-state flip-flop devices such as COD.

2. Description of the Related Art Conventionally, as a method for obtaining high-resolution color images using a plurality of solid-state 11IITA particles, for example, Japanese Patent Laid-Open No. 51-13
2719j3 publication. This method involves arranging three solid-state image sensors that correspond to the three primary color images of red, green, and blue separated by a three-primary color separation optical system. By arranging the image sensor and the solid-state image sensor for green color so that they are shifted by 172 tree pitches in the horizontal direction relative to the image, a broadband luminance signal is obtained and the resolution is improved for unenhanced images. The aim is to This is hereinafter referred to as "rG-RB pixel shifting method".

In the G-R8 pixel shifting method, the signal band of each R-G-B color is limited by the number of pixels of the element, as shown in Figure 3 (
172 ・f as shown in A).

(fs is the sampling frequency determined by the horizontal pixel pitch) If a frequency component higher than or equal to the frequency component is imaged, it becomes a folded component shown by a broken line, but as shown in Fig. 2, G and R-8
Since the image sensor is shifted by 172 pixels pitch in the horizontal direction, the aliasing components included in the G and R-B output signals have opposite phases.
By adding G=R+8>, the aliasing component can be canceled and a wideband signal up to f can be obtained, and the ratio of the NTSC luminance signal (R:G:B=0.3
: 0.59 : 0.11), but this broadband signal is used as the luminance signal of the NTSC output.

The problem that Hokumon is trying to solve: The color signal output method of the color prisoner decoy image device is as follows.
NTSC output, which limits the band of color 4g and multiplexes it with the luminance signal, is common, but R-G-8 output, which outputs R-G and 8 color signals independently, is also used. R
- An RG-8 output is also required for displaying the imaging signal on a G-B monitor or inputting a color image to an image processing device.

However, when performing R-G-8 output in a color solid-state imaging device using the G-R8 pixel shifting method, the layer image signals of each R-G-B color obtained from each image sensor are simply R
- Displayed on an R-G/B monitor as G-B output, and capturing images of high frequency components of 172 and 15 or more without color coding,
Since aliasing components with opposite phases occur in the imaging signal and in the R and B imaging signals, line (G) - magenta (Mg = R + 8) moiré and color shift occur on the monitor, reducing image quality. There was a problem with this.

The present invention solves the above-mentioned conventional drawbacks, and is a color prisoner imaging device using the G-R8 pixel shifting method.
It is an object of the present invention to provide a color solid layer image device that can reduce G-Mg moiré and color shift caused by aliasing components when performing G-8 output, and can obtain good image quality.

Means for Solving the Problems In order to solve the above problems, the color solid-state imaging device of the present invention includes a three primary color separation optical system, a solid-state imaging device for red color, a solid-state imaging device for blue color, and these solid-state image elements. a green solid-state optical image element arranged horizontally at a 1/2 pixel pitch with respect to the subject image; a synthesizing means; a second synthesizing means for obtaining red, green, and device color output signals by respectively front-framing the low-frequency components of the respective color signals and the high-frequency components of the signals obtained by the first synthesizing means; The configuration is equipped with the following.

Effect According to the above configuration, the low frequency components of the R-G 8 color signals and the R
- A signal obtained by adding the G-B color signals at a predetermined ratio and adding blue and high-frequency components of a wideband signal that does not include aliasing is used as an R-G-8 output signal, and the R-G-88 color signal is By replacing the high frequency range of the signal with a wideband signal that does not include aliasing, the aliasing components in each force signal are reduced.
It is possible to improve the image quality during RG/sunrise.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 5.

FIG. 1 is a block diagram of a color solid-state imaging device according to an embodiment of the present invention, in which 1 to 3 are image sensors, 4 to 6 are preprocessing circuits, 7 is a matrix circuit, 8 to 1o are mix circuits, 1
1 to 13 are signal processing circuits, and 14 to 16 are output terminals.

The red, green, and precolor images obtained by a three-primary color separation optical system (not shown) are projected onto image sensors 1, 2, and 3, respectively. Arrange as shown in Figure 2. R- obtained from the image sensor 1, 2°3
Each of the G-8 color signals is processed by a preprocessing circuit 4.5.6 such as sample hold, gain adjustment, and a time difference equivalent to a 172-pixel pitch between the G, R, and B signals. Note that each R-G-B color signal includes a folded component as shown in FIG.
Then, convert the R-G-88 color signal to an appropriate ratio (for example, R: G
: 8 = 0.33: 0.5: 0.17), and as shown in Fig. 3(B), a wideband signal Y = 0.33R + 0.5G + 0 with the aliasing component canceled is obtained.
．． 1B is synthesized. In mix circuit 8.9.10,
The low-frequency components RL-GL-BL of each R-G and B color signal and the high-frequency component YH of the wideband signal Y are extracted and added to obtain new color equalization symbols R', G', and 8'. There is. In the signal processing circuit 11, 12, and 13, after γ correction and edge enhancement are performed on each color signal of R', G', and B', the signal is sent to the output terminal 1.
R-G-B color signals are output on 4.15.16.

Specific configuration examples of mix circuits 8 to 10 are shown in Figures 4 and 5.
As shown in the figure. In the example shown in FIG. 4, the low-pass filter 17 extracts the low-frequency components of each color signal R-G-8, the bypass filter 18 extracts the high-frequency components of Y, and the extension circuit 19 extracts the high-frequency components of the Y signal. The time deviation caused by each filter 17 and 18 is corrected, and the low frequency component RL-GL-BL of the color signal RG-8 and the high frequency component YH of the wideband signal Y are added by the filter 20, and the color signal R'・G'・B'
is obtained. Note that the bypass filter 18 and the delay circuit 19 can be made common to each color, and only one can be used for the mix circuits 8 to 10.

In the example shown in FIG. 5, each color @@R, G-
Difference signals R-Y, G-Y, and B-Y between 8 and the wideband signal Y are obtained and input to the low-pass filter 22 to produce low-frequency components RL -YL and GL -YL of the difference signals.

By extracting BL-YL and adding it to the wideband signal Y delayed by the delay circuit 23 and the adder 24, the low frequency component RL -GL of each color signal is finally obtained. BL and the high frequency component of the wideband signal Y Add component YH=Y-YL and color @R'
・G'・B' is obtained. Note that the delay circuit 23 is
This is to compensate for the eight extension times of the low-pass filter 22, and can be made common to each color.

By performing the above signal processing, as shown in Figure 3 (C), the high frequency range of each color signal is replaced with the high frequency component YH of the wideband signal that does not include aliasing, and the high frequency component YH of the wideband signal that does not include aliasing components can be removed, and moiré and color shift of G-Mg can be reduced.

Note that the γ correction may be performed immediately after the preprocessing circuits 4 to 6, and the contour enhancement may be performed immediately after the matrix circuit 7.

Moreover, the imaging devices 1 to 3 include two such as CCD, MOS, CPD, etc.
It may be of any type as long as it is a dimension transport@element.

Effects of the Invention As described above, according to the present invention, although the G-R8 pixel shifting method is used, when R-G/B output is performed, G-M (J moiré and color shift) can be prevented. can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a color solid-state optical imaging device according to an embodiment of the present invention, FIG. A) is an explanatory diagram of the band characteristics of each R/G-B color signal, (B) is an explanatory diagram of the band characteristic of a wideband signal, and <C> is an explanatory diagram of the band characteristic of the R-G-8 output. Explanatory drawings, FIGS. 4 and 5 (each of which is a circuit block diagram of a mix circuit. 1.2.3...imaging element, 7...matrix circuit, 8.9.10...mix Circuit Agent Yoshihiro MorimotoFigure 1Figure 2Figure 3Figure 4

Claims (1)

[Claims] 1, 3 primary color separation optical system, a solid-state image sensor for red color, a solid-state image sensor for blue color, and a solid-state image sensor for green color arranged horizontally shifted by 1/2 pixel pitch from these solid-state image sensors with respect to the subject image. a first synthesizing means for adding each color signal obtained from each of the solid-state image sensors at a predetermined ratio, and a low frequency component of each of the color signals and a high frequency component of the signal obtained by the first synthesizing means. Add each component to create red, green,
A color solid-state imaging device comprising: a second combining means for obtaining output signals of each color of blue.